In general, a fuel cell includes an electrode for generating an electrochemical reaction with a fuel and an oxidizer, a polymer electrolyte membrane for transferring protons generated by the reaction, and a separator (commonly called a “separation plate” in the industry) for supporting the electrode and the polymer electrolyte membrane.
A polymer electrolyte fuel cell has been most spotlighted as a fuel cell for a vehicle. The polymer electrolyte fuel cell has advantages in that it has high efficiency and high current density and output density, it has a short starting time, it does not corrode, and it does not need to control an electrolyte because it uses a polymer electrolyte, compared to other types of fuel cells.
Furthermore, in the global vehicle industry, active research is being carried out on polymer electrolyte fuel cells because the polymer electrolyte fuel is an environmentally-friendly power source that discharges only water as exhaust gas.
This polymer electrolyte fuel cell can generate electrical energy while generating water and heat through an electrochemical reaction between fuel, including hydrogen, and an oxidizer, such as air.
That is, in the polymer electrolyte fuel cell, supplied fuel is separated into protons and electrons in the catalyst of the anode, and the separated protons are transferred to the cathode through a polymer electrolyte membrane. In this case, the separated protons are combined with a supplied oxidizer and electrons received through an external conductor, thereby generating electrical energy while generating water.
In an actual fuel cell for a vehicle, in order to obtain high potential, unit cells are stacked according to the required potential. The stacked unit cells are called a stack.
The electrode of a fuel cell includes a mixture of hydrogen ion carriers and a catalyst. In an initial operation after a fuel cell is fabricated, the activity of electrochemical reactions may be low.
The reason for this is that reactants are unable to reach the catalyst because the moving path of the reactants is clogged, the hydrogen ion carriers forming a triple phase interface are not easily hydrolyzed in the initial operation, and it is difficult to secure the continuous mobility of hydrogen ions and electrons.
For this reason, in order to secure maximum performance of fuel cells after the fuel cells are assembled in a fuel cell stack, that is, an electrical generation aggregate of the fuel cells which includes a membrane-electrode assembly including an electrode and a polymer electrolyte membrane and a separator, an activation and performance evaluation procedure needs to be performed on the fuel cells.
An object of the activation and performance evaluation is to remove remaining impurities that have flowed in a process of manufacturing a membrane-electrode assembly and a fuel cell stack, activate sites that do not participate in a reaction, secure a moving passage in which reactants may move to a catalyst, and secure a hydrogen ion passage by sufficiently hydrolyzing an electrolyte included in the polymer electrolyte membrane and an electrode. The activation of fuel cells is performed in various ways according to fuel cell manufacturers, but a major activation method is a long-time operation at a specific voltage.
After a stack of a plurality of fuel cells is fabricated, conventional equipment for activating fuel cells may perform activation and performance evaluation processes on the fuel cell stack by supplying fuel and an oxidizer to the fuel cells, applying electrical energy generated from the fuel cells to an electronic load device, and checking cell voltages.
In the activation and performance evaluation process of the fuel cell stack, the connectors of voltage measurement equipment are connected to terminals respectively protruded from the fuel cells of the fuel cell stack, an output cable connected to an electronic load device is connected to the output terminals of the fuel cell stack on both sides, and a fluid supply pipe for supplying fluids (e.g., hydrogen, air, and a coolant) to the fuel cells of the fuel cell stack is connected to the manifold of the fuel cell stack.
In the process of connecting the connectors of the voltage measurement equipment to the respective terminals protruded from the fuel cells of the fuel cell stack, the connectors and the terminals of the fuel cells are manually connected. Accordingly, in a conventional art, since the connectors of the voltage measurement equipment are manually connected to the terminals of the fuel cells of the fuel cell stack, workability may be low, a task time taken to connect the connectors and the terminals may be excessively consumed, and the fuel cell stack may be damaged when the connectors are connected to the terminals.
Furthermore, in the process of connecting the output cable, connected to the electronic load device, to the output terminals of the fuel cell stack on both sides, a worker engages a bus bar and the output cable, connected to the electronic load device, with the output terminals of the fuel cell stack using bolts. Accordingly, in a conventional art, a worker may be exposed to a danger of electric shock if he or she manually connects and disconnects the output cable to and from the output terminals of the fuel cell stack. That is, although the supply of hydrogen and air to the fuel cell stack is stopped, an electric current is generated due to an electrochemical reaction of hydrogen and air that remains in the fuel cell stack. Accordingly, a worker may experience an electric shock accident when separating the output cable from the output terminals.
Furthermore, in the process of connecting the fluid supply pipe for supplying a fluid to the fuel cells of the fuel cell stack to the manifold of the fuel cell stack, the fuel cell stack is manually pushed and connected to the fluid supply pipe of the activation equipment. Accordingly, in a conventional art, since the fuel cell stack of several tens of kilograms is manually pushed and connected to the fluid supply pipe of the activation equipment, workability is deteriorated. Furthermore, it is difficult to secure air-tightness between the fluid supply pipe and the manifold of the fuel cell stack when they are connected.
The above information disclosed in this Background section is only for the enhancement of understanding of the background of the inventive concept and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.